Recently, with the increase in aging population due to an increase in average lifespan and the development of an early diagnosis technology, the number of cancer patients has tended to abruptly increase. The statistics published by the Ministry of Health, Welfare and Family Affairs in 2008 show that if people live up to an average lifespan, one out of three Koreans has cancer. A radiation treatment is one of three cancer treatment methods together with surgery and anticancer therapy and has gradually increased its role. An object of the radiation treatment is to necrose a tumor or suppress growth of the tumor by concentrating high dose radiation on the tumor while minimizing damage to normal surrounding organs.
Brachytherapy is a therapy that treat a cancer by irradiating high dose radiation onto a tumor while minimizing damage to normal surrounding organs by directly injecting an isotope into the center or periphery of a tumor. Since the brachytherapy can be performed alone or in combination with an external radiation treatment and can directly irradiate the high dose radiation onto the tumor, the brachytherapy is widely known as a standard radiation therapy for a cervical cancer that is a female's representative disease. The brachytherapy is one of three-dimensional conformal radiation therapy that uses the effect that very high dose is irradiated onto a region adjacent to a source of the injected isotope but the dose rapidly decreases as a distance from the source increases on the basis of an inverse square law. Therefore, for the success of the brachytherapy, it is important to effectively arrange sources in the proximity of a tumor to be treated.